The present invention relates to the cleaning of process deposits from substrate processing chamber components.
In the processing of substrates, such as semiconductor wafers and displays, a substrate is placed in a process chamber and exposed to an energized gas to deposit or etch material on the substrate. During such processing, process residues are generated and deposited on internal surfaces in the chamber. For example, in sputter deposition processes, material sputtered from a target for deposition on a substrate also deposits on other component surfaces in the chamber, such as on deposition rings, shadow rings, wall liners, and focus rings. In subsequent process cycles, the deposited process residues can “flake off” of the chamber surfaces to fall upon and contaminate the substrate. Consequently, the deposited process residues must be periodically cleaned from the chamber surfaces.
However, it can be difficult to clean process deposits from components without excessively eroding the surface of the components. This can be especially true when cleaning process residues containing metals from components that are made of metal-containing materials. The metal-containing process deposits are difficult to remove because cleaning solutions suitable for their removal are also frequently reactive with other metals that are used to form chamber components. For example, a cleaning solution that is suitable for the removal of tantalum-containing process residues can also react with and erode chamber surfaces comprising titanium or aluminum. Thus, cleaning of metal-containing deposits from such surfaces can erode the components and require their frequent replacement.
The erosion of component surfaces can also be problematic when cleaning textured surfaces, such as surfaces formed by a “Lavacoat™” process. Such textured surfaces are desirable because they provide a “sticky” surface with crevices, depressions and protrusions to which process deposits adhere to reduce particle generation in the chamber. However, because the process deposits can get lodged in the pores and crevices of the surface, it is difficult to remove these deposits with conventional cleaning process. For example, cleaning the deposits with a conventional bead blasting process often results in the erosion of the protrusions of the textured surface, requiring frequent replacement and/or resurfacing of the component.
Thus, it is desirable to have a method of cleaning process deposits from surfaces of components without excessively eroding the surfaces. It is also desirable to have a method of selectively cleaning metal-containing process deposits from the metal surfaces of chamber components.